Multilayer wiring board

Abstract

There is provided a multilayer wiring board, which has a board body formed with two opposite main surfaces and includes a first resin insulating layer, a second resin insulating layer laminated to the first resin insulating layer and a wiring pattern arranged between the first and second resin insulating layers with a first surface of the wiring pattern abutting the first resin insulating layer and a second surface of the wiring pattern abutting the second resin insulating layer. The multilayer wiring board is characterized in that the wiring pattern extends in a plane direction of the board body and is embedded in both of the first and second resin insulating layers.

1 . A multilayer wiring board, comprising a board body formed with two opposite main surfaces and including a first resin insulating layer, a second resin insulating layer laminated to the first resin insulating layer and a wiring pattern arranged between the first and second resin insulating layers with a first surface of the wiring pattern abutting the first resin insulating layer and a second surface of the wiring pattern abutting the second resin insulating layer, the wiring pattern extending in a plane direction of the board body and being embedded in both of the first and second resin insulating layers. 
     
     
         2 . The multilayer wiring board according to  claim 1 , wherein the wiring pattern has a height ratio h 11 :h 12  of 1:9 to 8:2 where h 11  is the height of a first conductive portion of the wiring pattern embedded in the first resin insulating layer; and h 12  is the height of a second conductive portion of the wiring pattern embedded in the second resin insulating layer. 
     
     
         3 . The multilayer wiring board according to  claim 1 , wherein the wiring pattern has a width ratio W 1 :W 2  of 1:1 to 9:1 where W 1  is the maximum width of a first conductive portion of the wiring pattern embedded in the first resin insulating layer; and W 2  is the maximum width of a second conductive portion of the wiring pattern embedded in the second resin insulating layer. 
     
     
         4 . The multilayer wiring board according to  claim 1 , wherein the taper ratio of a cross section of a conductive portion of the wiring pattern embedded in the second resin insulating layer, taken perpendicular to a wiring direction of the wiring pattern, is in the range of 80% or higher. 
     
     
         5 . The multilayer wiring board according to  claim 1 , wherein the second resin insulating layer has a groove formed in a surface thereof abutting the second surface of the wiring pattern along a wiring direction of the wiring pattern; and wherein the wiring pattern has a protruding ridge formed on the second surface thereof and embedded in the groove of the second resin insulating layer. 
     
     
         6 . The multilayer wiring board according to  claim 5 , wherein the second resin insulating layer has a plurality of depressions formed in a surface thereof abutting the second surface of the wiring pattern; and wherein the wiring pattern has a plurality of protrusions formed on the second surface thereof and embedded in the depressions of the second resin insulating layer, respectively. 
     
     
         7 . The multilayer wiring board according to  claim 1 , wherein the wiring pattern is a fine wiring pattern with a maximum line width of 20 μm or less. 
     
     
         8 . The multilayer wiring board according to  claim 5 , wherein a depth of the groove is smaller than a thickness of the second resin insulating layer. 
     
     
         9 . The multilayer wiring board according to  claim 6 , wherein a depth of the depressions is smaller than a thickness of the second resin insulating layer. 
     
     
         10 . The multilayer wiring board according to  claim 5 , wherein the groove is formed with a roughened inner surface. 
     
     
         11 . The multilayer wiring board according to  claim 6 , wherein the depressions are each formed with a roughened inner surface. 
     
     
         12 . The multilayer wiring board according to  claim 1 , wherein the wiring pattern has a copper plating layer and a tin layer formed between the copper plating layer and the first resin insulating layer. 
     
     
         13 . The multilayer wiring board according to  claim 12 , wherein the wiring pattern has a silane coupling layer formed between the tin layer and the first resin insulating layer.